When electronic devices are manufactured, various plasma treatments are performed on an object to be processed. In a plasma processing apparatus for performing plasma treatment, a plasma is generated by exciting a gas supplied into a processing chamber. The object to be processed is processed by the plasma thus generated.
In the plasma processing apparatus, the object to be processed is mounted on a mounting table. The mounting table includes a lower electrode and an electrostatic chuck. The electrostatic chuck is provided on the lower electrode. The lower electrode is electrically connected to a high frequency power supply for generating a high frequency power. Further, a heater for heating the object to be processed is provided in the electrostatic chuck. The heater is electrically connected to a heater power supply via a power feeder. The power feeder is coated by a coating portion made of an insulating material. Moreover, a filter unit is provided between the power feeder and the heater power supply. The filter unit has therein an LC filter. The filter unit can suppress flow of the high frequency power supplied to the lower electrode into the heater power supply. Such a plasma processing apparatus is disclosed in Japanese Patent Application Publication No. 2011-135052.
Meanwhile, there are various methods for exciting a processing gas. Recently, a plasma processing apparatus for exciting a processing gas by using a microwave attracts attention.
With respect to a microwave, the coating portion is a dielectric material. Therefore, in the plasma processing apparatus using a microwave, the microwave propagates through the coating portion. The leakage of the microwave may affect various components of the plasma processing apparatus. For example, the microwave may flow into the heater power supply or cause malfunction of various measurement devices.